Application of water ring vacuum pump unit in condenser vacuum
The EVP company produces the equipment for the vacuum system of the steam turbine. The first is that there are obvious improvements in technology (which can compete directly with foreign brands), but also because of the power investment boom. The vacuum system is indispensable in the thermal power unit, its main function is:
(1) at the beginning of the unit starting to establish condenser vacuum when turbine inlet gas heating machine, steam in the condenser, if did not establish a certain vacuum condenser, steam in the condenser will make form positive pressure condenser, damage to equipment.
(2) keep the condenser vacuum in the process of unit operation, ensure the safe and economic operation of the unit for the condenser is in the process of running the internal in the vacuum state, imprecise due to pipe and shell, the air will leak, undermining the condenser vacuum, safe and economic operation of steam turbine. At the same time, when the air content is large, it will increase the oxygen content of the condensate and increase the corrosion of the equipment. The second will increase the heat transfer resistance and affect the cooling effect. At present, the vacuum system in a thermal power unit has a jet aspirator and a water ring vacuum pump (the ejector is divided into water and gas). The water ring vacuum pump has the following advantages:
It operates the economy. Under the starting condition, the suction capacity of the low vacuum is much larger than that of the ejector, which greatly reduces the starting time of the unit. In the running state, the energy consumption is only 23% of that of the water ejector.
The loss of soda is small.
The operation of the pump group is high, safe and easy to operate.
Small noise, compact structure, small footprint.
The disadvantage is that there is a large one-time investment. However, due to its obvious advantages, most of the newly-built thermal power plants adopt the water ring vacuum pump vacuum system, especially the high power units. Many power plants also replace the injection pump with water ring vacuum pump in the old unit reconstruction. At present, the water ring vacuum pump unit is widely used in the thermal power industry, and there are few articles about it. In this paper, a brief introduction to the complete set of water ring vacuum pump is made based on the actual situation of the company. Eccentric impeller in a nearly circular pump body, when the impeller rotates, according to the graphic direction arrow due to centrifugal force function, the injection pump body of water along the formation of vortex pump shell water ring vacuum pump structure 2. Suction mouth (3) vent 4. Pump body, so called water ring vacuum pump (also called liquid ring vacuum pump, can use other liquid work liquid). The inner surface of the water ring with the impeller wheel yi formed between A crescent-shaped space, when the impeller shifted from point A to point B, surrounded by the vessel between two adjacent blades gradually increase, gas sucked by the outside world. When the impeller is transferred from point C to point A, the corresponding cavity is greatly reduced, so that the previously absorbed gas is compressed. When the pressure reaches or slightly exceeds the atmospheric pressure, the gas is expelled. With the steady rotation of the impeller, the suction and exhaust processes are continuously carried out. So you can pump gas continuously. 1. The process is called an open-type unit, which consists of a water ring vacuum pump and a soda water separator. The working water is injected directly into the vacuum pump, and the gas and water mixture are discharged into the separator. The gas is discharged from above and the water is discharged from below. Open the unit small one-time investment, but because of its automation degree is not high, can provide water and need to use a lot of work, can only use the general water circulation, (but not with better water quality of condensate). As a result, only very few power plants are adopted, most of which are in this form in other industries.